The Top 5 Carbon Fibre Upgrades for the BMW G90 G99 M5

The 2025 BMW G90 G99 M5 is polarising by aesthetics; some claim it's the wrong direction, while others prefer its aggressive styling. While the hybrid powertrain offers staggering performance, the sheer scale of the car means it needs the right visual "muscle" to match its 700+ horsepower output.

At AUTOID, we believe the key to perfecting the G90 is leaning into its aggression while shedding that "stock" executive look. By utilising lightweight, high-strength materials, you can improve the power-to-weight ratio while defining the car's silhouette. If you’re ready to start your build, here are the top 5 carbon fibre upgrades we recommend for the new M5.

1. Front Splitter

The front end of the G90 is dominated by those massive cooling ducts. A carbon splitter is essential to "tie" the front bumper to the tarmac and extend the chin for a more dominant, track-ready look. High-quality splitters also help manage airflow under the chassis, increasing high-speed stability.

The Options:

• TRE PR-1 Carbon Splitter: Designed specifically for the G90/G99 chassis, this splitter is constructed from 2x2 weave pre-preg carbon fibre. It’s a multi-piece design that adds sharp, angular geometry to the front apron, providing a much-needed aggressive lower profile.
  
  
• BMW M Performance Front Splitter: For the purist who demands factory-level fit and finish. This genuine M Performance part is engineered to the highest standards, ensuring a perfect weave match to existing BMW carbon.
  
  

2. Rear Spoiler

The G90 has a massive rear deck, and the factory "gurney flap" can feel a bit underwhelming against the car's wide arches. A more pronounced spoiler is the most cost-effective way to transform the rear silhouette.

• TRE PR-1 Rear Spoiler: This pre-preg carbon wing features a classic "ducktail" kick. It’s designed to accentuate the G90's width, providing a sophisticated yet sporty finish. Shop G99 M5 Touring version here.
  
  
• ADRO Carbon Spoiler: If you want to push the envelope, ADRO’s aerodynamic design is the way to go. Their G90 spoiler features a more futuristic, high-kick aesthetic that makes a bold statement.
  
  

3. Rear Diffuser

With the quad exhaust tips being a hallmark of the M5, the diffuser is the centerpiece of the rear end.

The Selection:

• TRE PR-1 Rear Diffuser: This unit offers deep, aggressive fins that improve airflow transition from under the car. Built from lightweight pre-preg carbon, it adds a level of road presence the plastic factory trim can’t match.
  
  
• ADRO Diffuser: Known for its aerodynamic winglets, the ADRO diffuser visually widens the rear of the G90 M5, giving it a lower, wider stance.
  
  
• Alpha-N (via IND): For those chasing the ultimate in German engineering. Alpha-N components are world-renowned for their carbon quality and fitment precision.

4. Side Skirts

To connect the aggressive front splitter to the rear diffuser, you need side skirts. Without them, the side profile of the G90 G99 can look "waisted." Side skirts visually pull the car closer to the ground without compromising ride height.

The Choice:

• TRE PR-1 Side Skirts: These skirts offer a sleek, linear extension that adds a sharp edge to the M5's profile. They are UV-protected and designed to withstand the rigours of daily driving.
  
  
• ADRO Side Skirts: Featuring ADRO’s signature aero-winglets at the rear, these skirts add a complex, high-end look to the M5.

5. Carbon Fibre Bonnet / Hood

If you want to go beyond the "bolt-on" basics and enter the realm of elite builds, a carbon fibre hood is the ultimate statement piece. It’s one of the largest panels on the car, meaning the weight savings and visual impact are massive.

The Choice:

• SQ Carbon Hood: This is about cooling and visual drama. Often featuring vented designs that help heat escape that massive V8 hybrid engine bay, the SQ hood completely changes the "face" of the car.
  
  
• Alpha-N Carbon Bonnet: For a cleaner, more refined look. Alpha-N hoods often feature power domes that pay homage to legendary M5s of the past.
  
  

What does the community think of our modified G90 M5?

We posted our modified G90 M5 shop car on Reddit. Take a look at what they had to say:

Modified G90 M5
by u/AUTO_IDentity in BMW

 

 

Final Thoughts: Form & Function

The G90 M5 is a bold car, and while carbon fibre turns up the aggression, these mods are really about identity. By choosing high-quality pre-preg carbon from brands like TRE, ADRO, and Alpha-N, you ensure your M5 looks as fast as it actually is.

Shop Full BMW G90 M5 Saloon Carbon Range

Shop Full BMW G99 M5 Touring Carbon Range

Which carbon kit are you choosing for your G90? Let us know in the comments or reach out to our team for a bespoke build consultation.